Building my first battery!

baipin

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Hey everyone, new here, (but not new to LiFePO4 or DC campervan electrical)...

I'll be building a small cabin the size of a shipping container; 160 sq ft. which can be mounted on a truck (it'll mostly be stationary, but I'll travel with it every now and then); so durability and vibration-proofing are a must. It'll be something like a DIY Blissmobil.

Currently, I have roughly 7kW of 272Ah cells from Alibaba/Basen on the way. Planning on an 8s 24v arrangement. My largest power draw will be about 1800-2200W from an induction stove (if using one hob on max or both hobs on medium). I assume I'd want a 3000W PSW inverter to handle this? I am currently thinking of an OverkillSolar 100Ah 24v 8s BMS to pair it with. But, when using the induction cookers I'd be maxing it out at 100 amps. Is this safe, or should I go with something larger? I am in Canada so I want one with low temp cutoff.

Thanks.
 

MisterSandals

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My largest power draw will be about 1800-2200W from an induction stove
This might not require a PSW inverter.
Or...
Is there such a thing as a 24v DC induction stove? Seems unnecessarily wasteful to convert DC to AC to power a heating element.

And, propane is my fuel of choice for mobile cooking: cheap and easy!
 

MrNatural22

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Found this one but there are others out there. ✌️

 

baipin

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This might not require a PSW inverter.
Or...
Is there such a thing as a 24v DC induction stove? Seems unnecessarily wasteful to convert DC to AC to power a heating element.

And, propane is my fuel of choice for mobile cooking: cheap and easy!

I agree. Huge loses, huge expense. I'd only need a 200W PSW if it weren't for the damn induction stove! Only other large draw would be the fridge. As it is, I have a Dometic CC40 in my Subaru camper that runs for a few days off of a little 0.5kW LiFePO4. The more I can keep on 12v or 24v the merrier (and it seems I can run nearly everything off of 24v that could be run on 12v.

I assume if, in the future I want to charge batteries from a 12v alternator, all I would need is a DC-DC charger?
 

chrisski

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Found this one but there are others out there
As I read it, I see 325 watts for this device. As far as I know, 325 watts won’t brew a cup of coffee in a reasonable amount of time. 400 watts is what a crock pot can use to slow oil something.

I really think Low VOltage DC is totally inadequate for high wattage appliances. You want to be able to plug these appliances in, and with amperage that high at 12 or 24 volts, it’s just not practical with was thick as the wire need to be.

I’d like to see 700 watts, or closer to 1000 watts. At 12 volts, that can be 58 - 80 amps; at 24 volts 26 to 40 amps. That type of current you can't just plug into the wall you need to measure wire length, calculate loss and then size wire for that and amps city.
 

MrNatural22

🌞SW sunshine =⚡️⚡️lit up thru the darkness✌️
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As I read it, I see 325 watts for this device. As far as I know, 325 watts won’t brew a cup of coffee in a reasonable amount of time. 400 watts is what a crock pot can use to slow oil something.

I really think Low VOltage DC is totally inadequate for high wattage appliances. You want to be able to plug these appliances in, and with amperage that high at 12 or 24 volts, it’s just not practical with was thick as the wire need to be.

I’d like to see 700 watts, or closer to 1000 watts. At 12 volts, that can be 58 - 80 amps; at 24 volts 26 to 40 amps. That type of current you can't just plug into the wall you need to measure wire length, calculate loss and then size wire for that and amps city.

I believe in the list on the first link it lists a 325w solar PV. And a LiFePo 24v battery is listed in the brochure listing.
If you watch the video it lists the cooker as 700w.✌️
 

baipin

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I believe in the list on the first link it lists a 325w solar PV. And a LiFePo 24v battery is listed in the brochure listing.
If you watch the video it lists the cooker as 700w.✌️
Here's another I found: https://www.alibaba.com/product-detail/Technique-Chuhe-Induction-Cooker-24V-Cheap_60653944245.html

I prefer the built-in designs for a number of reasons. Energy is energy though, and it does take a lot of wattage to boil water. This brings me back to my initial question though; is 2400W (24V 100A BMS) enough for an induction cooker; both hobs on medium, say 1000W each? I'd have a negligible 100W running in addition to that (LED lights and whatnot).
 

MisterSandals

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is 2400W (24V 100A BMS) enough for an induction cooker;
Not all BMS's are created and rated equally. Some cheap BMS's need to be oversized by up to 50% and others are good at rated amps. When you pick a BMS, its a good question to ask an unbiased audience if possible.

A BMS running near capacity will likely run hotter and have a shorter life. What happens when a BMS reaches max current is probably different from maker to maker too.
 

baipin

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Not all BMS's are created and rated equally. Some cheap BMS's need to be oversized by up to 50% and others are good at rated amps. When you pick a BMS, its a good question to ask an unbiased audience if possible.

A BMS running near capacity will likely run hotter and have a shorter life. What happens when a BMS reaches max current is probably different from maker to maker too.
That's what I figured. The one I'm thinking of running is the 24v 8s 100A from Overkill Solar
 

MisterSandals

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Straight from the horse:
 

lance

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And, propane is my fuel of choice for mobile cooking: cheap and easy!
Relatively cheap and easy but, propane doesn't fall from the sky, (like manna from heaven!), for free! Agreed though when it comes to stove top cooking; I can't do electric and do have a 17lb tank in locker as part of my plan. But, when it comes time to refill the tank and we've gotta head into town in the middle of the zombie apocalypse, we might be wishing we'd adapted to these induction cook tops.
 
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